Streaming data includes media and multimedia files, such as video clips and audio, that begin playing as they are received. The media is delivered in a “stream” from the server to the user. Streaming video, for example, is a sequence of moving images that are sent in compressed form over the Internet and displayed as they arrive. As another example, streaming media is streaming video with sound.
The use of streaming media is growing in popularity. Users of the internet, for example, can view videos or listen to music without waiting for large data files to download to the computer. For video and audio files, for instance, the user needs a video/audio player to uncompress the data and send it to a display or speakers.
Unfortunately, streaming media is susceptible to unwanted, malicious, and surreptitious attacks, especially since users cannot verify that an end of streaming media has been received. A malicious third party could use a known or predictable end of stream marker to change the software of the user from streaming mode to command mode. Once in command mode, the malicious third party could obtain the trust and privileges of the streaming media server.
In other instances, some viruses can attach themselves to various locations of program files and replace code, fill in open spaces in the code, or create companion files to work with an executable file. Parasitic type viruses, for example, can attach themselves to the beginning or end of a file. When the virus attaches to the end of the file, the virus also changes the beginning so that the viral code is launched first. A worm, for example, may be able to attach itself to the end of the data stream while the stream is being downloaded. The worm installs itself to the computer system and then runs a spreading routine and payload. Worms can even be designed to copy themselves and penetrate other users on a network.